A 1988 survey published by the Foundation for Advancements in Science and Education
also found styrene in human fatty tissue with a frequency of 100% at levels from 8 to
350 nanograms/gram (ng/g). The 350 ng/g level is one third of levels known to cause
neurotoxic symptoms.[5] determined that Styrofoam
drinking
leach Styrofoam into the liquids they contain. The cups apparently lose weight during
the time they are at use. The studies showed that tea with lemon produced the most
marked change in the weight of the foam cup.[1]

Although there is evidence that styrene causes cancer in animals, it has not yet been
proven to cause cancer in humans. Styrene primarily exhibits its toxicity to humans as
a neurotoxin by attacking the central and peripheral nervous systems. The accumulation
of
these highly lipid-soluble (fat-soluble) materials in the lipid-rich tissues of the brain,
spinal cord, and peripheral nerves is correlated with acute or chronic functional
impairment of
the nervous system. [3]

For example, women exposed to low concentrations of styrene vapors in the workplace
are known to have a variety of neurotoxic and menstrual problems. A Russian study of
110 women exposed to styrene vapors at levels about 5 mg/m3 demonstrated menstrual
disorders, particularly perturbations of the menstrual cycle and a hypermenorrhea
(unusually heavy flow of menses during the menstrual cycle) syndrome. Styrene-
exposed women often suffered from metabolic disturbances occurring during pregnancy.
[4]

Most interesting is the degradation of food that contains vitamin A (betacarotene).
In packaged foods with the addition of heat (such as microwave temperatures),
vitamin A will decompose and produce m-xylene, toluene, and 2,6-dimethylnaphthalene.
Toluene will aggressively dissolve polystyrene. This renders polystyrene as an unsuitable
package for containing or microwaving products that contain vitamin A.[6]

Even if styrene were declared non-carcinogenic, is it "safe"
as a food additive? Serious questions exist as to the carcinogenic and mutagenic impact
of metabolites of styrene monomer (styrene-7,8-oxide, a
known
carcinogen, and mandelic acid, a known mutagen), while the neurotoxic impact of this
monomer may outstrip the carcinogenic and mutagenic implications. Further, 100
percent
of the public has levels of styrene monomer at concentrations between 8-350 ng/g.[2] An obvious source of the monomer is food and beverage
containers. Finally, neurotoxic problems occur at levels within one order of magnitude
of
known exposure concentrations currently found in adipose tissue. [3]

The term "food additive" plainly includes not only substances that are intentionally
added to foods, such as direct food additives..., but also substances that are not
intentionally added but nevertheless contact and are reasonably expected to migrate to
food.[5] Therefore, styrene monomer that migrates into
food
from packaging is by definition a food additive. It has been shown that styrene monomer
can affect the quality of food products at known migration levels, and over 50 percent of
the migration of residual monomer occurs within twenty-four hours (within the normal
shelf life of many food products.[6]